The subject application relates generally to headers for agricultural harvesters. In particular, the subject application relates to a header including an improved cutting knife assembly having overlapping sickle sections.
Agricultural harvesters such as combine harvesters are well known apparatuses for harvesting grain crops. An agricultural harvester is typically a self-propelled vehicle which includes a feederhouse and mechanisms downstream of the feederhouse for separating grain from other crop material. A header is attached to the front of the harvester and includes mechanisms for cutting crop, gathering crop and delivering crop to the harvester's feederhouse. A typical crop cutter includes a stationary knife and a reciprocating knife which together act as shears that cut crop near the ground. After cutting, the crop is gathered e.g., by a harvesting reel which feeds the cut crop to a conveyor system that transports the cut crop to the harvester's feederhouse.
Typical reciprocating knife assemblies include knife blades formed from a plurality of sickle sections which are bolted to a knife back, some of which are also bolted to a knife head. In the event a sickle section becomes dulled or damaged and requires replacement, the affected section is unbolted and replaced by a new section. However, such repair can be time consuming and labor intensive, especially if several sickle sections require replacement. This is because conventional sickle sections each require two or more fasteners to secure the sickle sections to the underlying knife back and possibly the knife head.
Still further, the many fasteners required to secure the sickle sections to the knife back and knife head add an undesirable number of components and additional mass to the assembly. This is problematic in the sense that the more massive the knife assembly the more energy is required to propel the reciprocating blade in one direction then stop the blade and propel it in the opposite direction. Consequently, excessive mass combined with changes in velocity (acceleration/deceleration cycles) at each end of the knife stroke detrimentally affects knife speed which, in turn, introduces vibration and can result in slower cutting, slower combine ground speed and less than optimal harvesting productivity, while the increased number of components adds to manufacturing and maintenance complexity.